Temperature protection switch biased against scroll compressor shell

ABSTRACT

A sealed compressor is provided with a temperature sensor biased against an outer surface of its shell. By biasing the temperature sensor against the shell, good contact between the temperature sensor and the shell is ensured. Also by use of molded material around the senor, the sensor is insulated from ambient air, increasing the accuracy of the sensor.

BACKGROUND OF THE INVENTION

This application relates to a temperature protection switch which senses an unduly high temperature, and operates to stop operation of a compressor motor, and wherein the switch is biased against an outer surface of the compressor shell.

Refrigerant compressors are used in refrigerant systems. In a typical refrigerant compressor, a compressor pump unit and its motor are mounted within a hermetically sealed shell. Typically, suction refrigerant is directed into this shell, and serves to pass over a compressor motor, cooling the motor.

Various problems can occur during the operation of a refrigerant compressor. One often experienced problem is a loss of charge situation. In such situations, the amount of refrigerant within the refrigerant system is reduced, such as by a leak. When this occurs, there may be insufficient refrigerant to cool the motor. Other problems can occur, and can result in unduly high temperatures within the compressor. It is desirable to sense these unduly high temperatures accurately, and stop operation of the compressor motor when they occur. Thus, various methods have been provided in refrigerant compressors to sense unduly high temperatures. One known sensor is fixed to an outer surface of the refrigerant compressor housing shell. However, there have been some challenges in maintaining this sensor attached securely to the outer shell.

SUMMARY OF THE INVENTION

In a disclosed embodiment of this invention, a temperature sensor for a refrigerant compressor is biased against an outer surface of the compressor shell. In this manner, continuous good contact between the temperature sensor and the compressor shell is ensured. Additionally, use of a molded material around the sensor serves to insulate it from ambient air circulating around the sensor, thus increasing the sensing accuracy.

These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view through a refrigerant compressor incorporating the present invention.

FIG. 2 shows a second embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A compressor 20 is illustrated in FIG. 1, and includes an electric motor 22 for driving a shaft 24. As illustrated in this figure, the compressor is a scroll compressor having an orbiting scroll member 26 and a non-orbiting scroll member 28. As known, refrigerant enters a housing shell defined by upper shell 30 and center shell 32, through a suction tube 29. This refrigerant is delivered into a suction chamber 17 and serves to cool the motor 22. Refrigerant in the suction chamber 17 also moves into compression chambers defined between the scroll elements 26 and 28, and is compressed. The compressed refrigerant is directed through a discharge port 18 into a discharge chamber 19. This compressed refrigerant is then delivered downstream to refrigerant system components through a discharge tube 13. Refrigerant returns from downstream components back through the suction tube 29.

The compressor as described at this point is as known in the art. As mentioned above, for several reasons, it is desirable to monitor the temperature within the compressor, and stop operation should the compressor temperature become unduly high. Thus, temperature sensor 34, which may be any type of known temperature sensor, is incorporated onto the upper surface of the housing upper shell 30. A molded plug 36 has ears 42 which snap into openings 40 in a fence 38. Fence 38 is welded to the upper surface of the upper shell 30. The molded plug serves to bias the temperature sensor 34 against the upper shell, and thus ensure good contact, in addition to insulating the sensor from the lower temperature ambient air.

Should the sensor 34 sense that the temperature within the compressor is unduly high, a signal is sent to a controller 44, which stops operation of the motor 22.

The molded plug is preferably molded of a suitable plastic, which will have the required resilience to bias the temperature sensor against the upper shell.

FIG. 2 shows another embodiment wherein the sensor 134 and molded plug 136 are on the side of upper shell 30 Although an embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention. 

1. A sealed compressor comprising: a compressor pump unit and an electric motor; a housing shell sealing said compressor pump unit and said motor; and a temperature sensor attached to an outer surface of said housing shell, and a bias force holding said temperature sensor against said outer surface.
 2. The compressor as set forth in claim 1, wherein said temperature sensor is biased against the outer surface by a molded component.
 3. The compressor as set forth in claim 2, wherein said molded component is held within a rigid structure which is fixed to the outer surface.
 4. The compressor as set forth in claim 3, wherein said housing shell includes a center shell and an upper shell, and wherein said temperature sensor is in contact with said upper shell.
 5. The compressor as set forth in claim 3, wherein said molded component is formed of a resilient material and snaps into openings in said structure.
 6. The compressor as set forth in claim 1, wherein said compressor pump unit is a scroll compressor.
 7. The compressor as set forth in claim 1, wherein said temperature sensor communicates with a control for selectively stopping operation of the electric motor. 